Abstract : Introduction : Transient elevation of liver enzymes is reported in 9 % of patients on olanzapine. However, rare cases of symptomatic hepatotoxicity associated with olanzapine use have been reported in the literature. This case report describes a woman who presented acute hepatitis linked to the use of olanzapine. Similar reports in the literature are also analyzed. Observation : A 43-year-old female patient, treated for bipolar disorder type I by sodium valproate 1500 mg/d, was admitted to hospital for management of a manic episode. Her liver tests at admission were normal. As soon as she was admitted to hospital, the patient was treated by olanzapine 10 mg/day, which was increased to 20 mg/day over 2 weeks, and diazepam, in addition to the sodium valproate 1500 mg/d. Three days after the increase of olanzapine to 20 mg, the patient pre- sented with mucocutaneous jaundice, dark urine with pruritus and vomiting, and a marked alteration of liver enzymes. No etiology was found to explain this hepatotoxicity other than drug origin. Conclusion : This case report emphasizes the need for a baseline hepatic evaluation before starting olanzapine therapy and regular monitoring of liver enzyme levels, especially among at risk patients.